Borax, also known as sodium borate, sodium tetraborate, or disodium tetraborate, is an important boron compound, a mineral, and a salt of boric acid. It is usually a white powder consisting of soft colorless crystals that dissolve easily in water.

Borax has a wide variety of uses. It is a component of many detergents, cosmetics, and enamel glazes. It is also used to make buffer solutions in biochemistry, as a fire retardant, as an anti-fungal compound for fiberglass, as a flux in metallurgy, neutron-capture shields for radioactive sources, a texturing agent in cooking, and as a precursor for other boron compounds.

The term borax is used for a number of closely related minerals or chemical compounds that differ in their crystal water content, but usually refers to the decahydrate. Commercially sold borax is usually partially dehydrated.

Sodium Borate

Identifiers

CAS number

1303-96-4

UNII

91MBZ8H3QO

EC number

215-540-4

ChEMBL

CHEMBL1076681

Color

White power or Colorless translucent crystals

Properties

Molecular formula

Na2B4O7*10H2O or Na2[B4O5(OH)4]*8H2O

Molar mass

381.37 (decahydrate)

Appearance

white solid

Density

1.73 g/cm3 (solid)

Melting point

743 Celsius degree (anhydrous)

Boiling point

1575 Celsius degree

Related compounds

Other anions

sodium gallate

Other cations

Potassium tetraborate

Related compounds

Boric acid, sodium perborate

Use

Household products

Borax is used in various household laundry and cleaning products, including the " 20 Mule Team Borax " laundry booster and " Boraxo " powdered hand soap.

Buffer

Sodium borate is used in biochemical and chemical laboratories to make buffers, e. g. for gel electrophoresis of DNA, such as TBE or the newer SB buffer or BBS ( borate buffered saline ) in coating procedures.

Co-complexing

Borax as a source of borate has been used to take advantage of the co-complexing ability of borate with other agents in water to form complex ions with various substances. Borate and a suitable polymer bed are used to chromatograph non- glycosylated hemoglobin differentially from glycosylated hemoglobin (chiefly HbA1c ), which is an indicator of long term hyperglycemia in diabetes mellitus. Borate and a proprietary synthetic amino acid, Deselex (from Henkel ) have been used to complex water " hardness" cations to make a non- precipitating water " softener" .

Flux

A mixture of borax and ammonium chloride is used as a flux when welding iron and steel. It lowers the melting point of the unwanted iron oxide (scale), allowing it to run off. Borax is also used mixed with water as a flux when soldering jewelry metals such as gold or silver. It allows the molten solder to flow evenly over the joint in question. Borax is also a good flux for ' pre-tinning' tungsten with zinc - making the tungsten soft-solderable.

Small-scale mining

Borax is replacing mercury as the preferred method for extracting gold in small-scale mining facilities. The method is called the borax method and is used in the Philippines.

Putty

A rubbery polymer sometimes called flubber, gluep or glurch can be made by cross linking polyvinyl acetate with a borax. Making flubber from polyvinyl acetate based glues, such as Elmer' s Glue, and borax is a common elementary education experiment.

Food additive

Borax, given the E number E285, is used as a food additive in some countries, but is banned in the US. As a consequence, certain foods, such as caviar, produced for sale in the US contain higher levels of salt to assist preservation. Its use as a cooking ingredient is to add a firm rubbery texture to the food, or as a preservative. In oriental cooking it is mostly used for its texturing properties. In Asia, Borax was found to have been added to some Chinese foods like hand-pulled noodles lamian and some rice noodles like Shahe fen, Kway Teow, and Chee Cheong Fun recipes. In Indonesia it is a common, but forbidden, additive to such foods as noodles, bakso (meatballs), and steamed rice.

Other uses

1)Ingredient in enamel glazes2)Component of glass, pottery, and ceramics3)Borax can be used as an additive in ceramic slips and glazes to improvefit on wet, greenware, and bisque.4) Fire retardant5) Anti-fungal compound for fiberglass and cellulose insulation6)Moth proofing 10% solution for wool7)Anti-fungal foot soak8)Precursor for sodium perborate monohydrate that is used in detergents9)as well as for boric acid and other borates10) Tackifier ingredient in casein, starch and dextrin based adhesives11)Precursor for Boric acid, a tackifier ingredient in polyvinyl acetate12) polyvinyl alcohol based adhesives13) Fluoride detoxification14)Treatment for thrush in horses ' hooves15)Used to make indelible ink for dip pens by dissolving shellac into heated borax16)Curing agent for snake skins17)Curing agent for salmon eggs, for use in sport fishing for salmon18)Swimming pool buffering agent to control the pH19) Neutron absorber, used in nuclear reactors and spent fuel pools to control reactivity and to shut down a nuclear chain reaction20)As a micronutrient fertilizer to correct boron-deficient soils.21)To clean the brain cavity of a skull for mounting22)To color fires with a green tint23)Was traditionally used to coat dry-cured meats such as hams to protect them from becoming fly-blown during further storage.24)Is found in some commercial vitamin supplements25)For stopping car radiator and engine block leaks26)As an important component in Slime27)Is used by the modern Blacksmith in the process of Forge Welding.